The Biostatistics Core serves as the resource for study design, statistics, and database expertise for the Program Project Grant in Bone Marrow Transplantation (BMT) and These resources are grouped as follows: 1) Design and biostatistics consultation including: planning of new studies, with regard to design, estimation of study size requirements, methods for randomization (where appropriate) and plans for statistical analysis; monitoring of current studies, statistical analysis and scientific reporting of study results of animal studies and clinical trials. 2) Coordinating data collection and management for current studies and development of plans for data collection for new studies, including forms design and modification where needed, procedures for entering and tracking patients, aid in accessing data for monitoring studies in process and reporting of study results. 3) Procedures for assuring quality of the data collected and production of management reports for administrative and scientific functions, patient accrual, patient status, quality of the data, work progress in tracking patients and special reports requested by Investigators; 4) Aid in assembling, summarizing and analyzing PPG project data for scientific reports for seminars, national and international meetings and for publication in scientific journals; 5) Liaison with the hospital-supported maintainers of the BMT database, including consultation on systems for data storage and access, development of systems improvements, trouble shooting, collaboration in report development and collaboration in training of investigators, data managers and other personnel in the use of the database. The Biostatistics Core has an established and experienced team in place. Computer and data systems have been developed and are operational for fulfilling the missions described above. The team is composed of a Core Leader, a Core co-leader, two Biostatisticians, a Clinical Trials Coordinator and an expert outside consultant.